Yarn texturizing method and apparatus



Nov. 21, 1967 J. w. l. HElJNlS 3,353,239

YARN TEXTURIZING MET-HOD AND APPARATUS 2 Sheets-Sheet 1 Filed Jan. 25, 1965 q fl T 6 INVENTOR.

. Q I ll JAMES WATT IJSBRAND HEIJNIS ATTORNEY Nov. 21, 1967 J. w. HEIJNIS I YARN TEXTURIZING METHOD AND APPARATUS 2 Sheets-Sheet 2 Filed Jan. 25, 1965 FIG. 3

FIG. 2

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BY %'ORNEY United States Patent 3,353,239 YARN TEXTURIZING METHOD AND APPARATUS James W. I. Heijnis, Arnhem, Netherlands, assignor to American Erika Corporation, Enka, N.C., a corporation of Delaware Filed Jan. 25, 1965, Ser. No. 427,828

Claims priority, application Netherlands, Feb. 1, 1964,

64-844 7 Claims. (Cl. 28-1) The present invention relates to the preparation of textile fiber for commercial use and more particularly to an apparatus for texturizing synthetic polymeric yarns, tow, or roving by the stufferbox principle.

The stuiferbox concept of crimping linear fibers and filaments is well known. Such apparatus generally consists of a pair of smooth, cylindrical parallel rollers which coact to grip and feed yarn into a crimping chamber. The chamber, generally having a spring-biased or weighted discharge door, forms a substantially closed pressure zone. As the filamentary material is fed by the rollers into the stuffing chamber, it loops back and forth upon itself, forming a wad. This wad is compressed in its passage through the chamber by the friction of the side walls and the weighted discharge door. The action of the rollers in feeding additional yarn into the chamber produces crimps therein which can be effectively set by heat or fluid treatment. The crimped thread is withdrawn from the stuiferbox at a proportionate rate to the in-feed of the rollers. The yarn being fed to the rollers is generally pretreated in a known manner to soften it. Such a method and apparatus for producing crimped, textile fibers from a multi strand yarn, commonly referred to as tow, is disclosed in US. Patent No. 2,575,781.

The tow crimping process, utilizing the stufferbox principle, is carried out by introducing a plurality of filaments or bundle of fibers in the form of a roving into a stuiferbox crimping device where a permanent crimp may be imparted to the filament bundle. The smooth, cylindrical stuffing rollers force the yarn into the crimping chamber and the yarn is crimped in one direction only. The roving or tow is then withdrawn from the stuiferbox and cut by conventional means into short, staple length. This tow, which is provided almost exclusively with a unidimensional crimp in the stulferbox, has the disadvantage in that it produces staple fibers of relatively low bulk and tows which, on being processed into combed slivers, give rise to comparatively poor web formation. Moreover, in the conventional stulferbox apparatus, there often occurs slippage between the tow and the feed rollers. This slippage produces straight, virtually uncrimped lengths of tow, thus decreasing the fiber quality.

This problem of low bulk and non-uniform crimping of tow has been dealt with in prior patents. An early method of producing a high bulk tow or roving by linearly curling bundles of thread in two dimensions is found in US. Patent No. 2,326,174. In this patent, thread bundles of cellulose acetate are conducted between two successive pairs of gears, the axial planes of which are inclined at an angle, the one to the other, to produce a double-curve yarn. However, crimped yarn produced by gear crimping devices has never proved as satisfactory as that produced by stufferbox apparatus. Difficulties are encountered in producing a uniform crimp and in setting the crimp in the rapidly moving yarn when using the gear crimp apparatus.

Another patent dealing with two-stage crimping of textile fibers is US. Patent No. 2,647,285. In this patent, fibers are mechanically crimped by a gear wheel device and the crimp is set into the fibers in a separate setting zone. This setting zone is disclosed to be an enclosed box into which the crimped fibers are dumped, compacted, and held under 3,353,239 Patented Nov. 21, 1967 pressure while being treated with a setting agent. The treating box is shown to have a spring-biased discharge door for releasing the fibers. However, this device does not produce a multidimensional crimp in the yarn. The second stage or treating box is utilized only to set the initial gear Wheel crimp while the fibers are held under pressure. It is an object of the present invention to produce a high bulk, uniformly textured yarn not having the disadvantages heretofore pointed out.

An object of the present invention is to provide a novel method of producing crimped tows in which uniformity of crimp, high bulk level, and improved web formation can be obtained.

Another object of the present invention is to provide a unique stufferbox apparatus for producing crimped tows in which uniformity of crimp, high bulk level, and improved web formation can be obtained.

Another object of this invention is to provide a stuiferbox crimping device for crimping tow or roving in which slippage between the tow and the crimping rollers is prevented.

An additional object of this invention is to provide apparatus for producing a multidirectional crimp to textile yarn, in the form of a tow, by use of a modified stuiferbox crimping apparatus.

A still further object of this invention is to provide a stuiferbox apparatus for crimping a plurality of filaments in the form of a tow in which the tow or yarn bundle can be maintained on the mid-surface of the crimping rollers, thus preventing yarn damage due to frictional contact with the walls of the chamber.

The present invention consists of a conventional stuiferbox chamber containing a pair of yarn-gripping rollers for introducing textile tow into the box. The surfaces of the rollers which grip the filamentary material are designed with a curved, ridged, or corrugated profile, the axis of such corrugations extending peripherally about the circumference of the rollers. These curved, yarn-contacting faces grip the tow or roving being fed to the stufferbox chamber and crimp the tow in a direction perpendicular to the crimp produced to the stulferbox chamber as the tow is simultaneously fed into the stulferbox.

With the crimping roller surfaces designed according to the present invention, it has surprisingly been found that fibers and tows subjected thereto show a complex, multidirectional crimp, an improved bulk and web formation, and result in better cohesion during further processing of the tows into combed slivers by the converter system. It has been found that slightly varying the distance between the roller surfaces at certain positions along the corrugations in the roller surfaces additionally favorably influences the multidirectional crimp and coherency of the filaments in the tow.

The larger contact surface of the rollers with the tow prevents the slippage heretofore experienced with fiat con ventional rollers and results in fibers of improved uniformity. Moreover, because of this increased surface area, the external pressure on the stufiing rolls required to effectively grip the yarn can be reduced.

According to the invention, the curved profile created in the gripping face of the stufiing rollers is located in such a way that ridges of one stufiing roller are radially opposite grooves of the other roller and extend into the grooves in intermeshing relationship. The coaction of the roller surfaces is such that the distance between the surfaces, at

any point on the axial width of the rollers, remains approximately constant. The invention will be better understood by reference to the following detailed explanation of the apparatus and the accompanying drawings.

FIG. 1 shows, in section, a conventional stuiferbox crimping apparatus.

FIG. 2, a partial section taken along line II----II of FIG. 1, shows the cooperating relationship of the roller surfaces and one particular configuration of the surfaces employing the concepts of the present invention.

FIG. 3 shows, in section and on a larger scale, the detail of the pair of ridged stuffer rollers shown in FIG. 2 and is taken along line IIIIII of FIG. 1.

FIG. 4 shows, in partial section, a modification of the surface arrangement of the stuffing rollers employing the concepts of the present invention.

In FIG. 1, uncrimped tow 1 is fed through auxiliary guide rollers 2 to crimping and stufiing rollers 3 and 4 which rotate on shafts 5 and 6 in the direction indicated by the arrows. The stufling rollers 3 and 4 are biased in yarn-gripping relationship by conventional means (not shown). The yarn tow is gripped by the surface of the stufiing rollers and is forced, while simultaneously being crimped thereby, into a crimping chamber 7 contiguous with said rollers. The outlet of the crimping chamber is provided with a discharge opening closed by hinged door 8 which is biased closed by means of weight 9. The weighted door, as well as the friction between the tow and the walls of the crimping chamber, exert a pressure and impose an additional crimp on the tow. The tow may be preheated in conventional manner prior to its being fed by the crimping rollers to soften the filamentary material, and the crimping chamber may be subjected to heating or cooling to additionally set the crimped yarn.

The crimped tow 10 may be withdrawn from the chamber by conventional winding means or by the feed rollers of a device used for cutting fibers from the tow. The particular embodiment of the crimping chamber as well as the tow removing means may be varied in many ways and forms no part of the present invention.

FIG. 2 shows in partial section the details of the two crimping rollers 3 and 4. The crimping surfaces are shown in profile and are constructed in the form of ridges 11 and grooves 112. As shown, the axis of the ridges and grooves is perpendicular to the axis of rotation of the stuffing rollers and extends circumferentially about the periphery of the rollers. The tow which is compacted and crimped between the rollers is indicated at 13 and completely fills the space between the rollers. The auxiliary rollers 2 ('FIG. 1), which feed the yarn to the stufiing rollers, may also have similar surface configuration.

FIG. 3 shows, in enlarged section, the more detailed construction of the ridges and grooves shown in FIG. 2 and is taken on line III-III (FIG. 1) slightly downstream of the closest point of approach of rollers 3 and 4. The grooves 12 are shown to be curved while the ridges 11 are angular in shape. It has been found that such a surface configuration improves the bite of the roller surfaces and favorably influences the multidirectional crimp produced in the tow. A non-uniform clearance between the roller surfaces is produced by the difference in configuration of the groove and the ridge. The use of nonuniform clearances between the gripping surfaces of crimping gears for longitudinally crimping a filamentary material is disclosed in US. Patent No. 2,090,669.

BIG. 4 shows a modified form of rollers 3 and 4 in which the yarn-gripping surfaces are alternately concave and convex and intermesh to form a tow passageway 14. The curvature of the surfaces is designed so as to present a reduced clearance at the edges of the tow passageway. This construction insures that the yarn bundle will not come between the stufiing rollers and the walls 15 and 16 of the crimping chamber.

The yarn bundle, as it passes between the crimping rollers, is shaped and crimped in a transverse direction to the longitudinal crimp imposed by the wad formation in the main stufferbox chamber. The filaments of the bundle or tow are not individually crimped by the corrugations extending peripherally about the circumference of the rollers, but the tow leaving the stufiFerbox is provided with a greater degree of bulk and a more cohesive web may be formed from the tow in subsequent opera tions. The particular configuration of the roller surfaces may vary widely without departing from the scope of the present invention, and the specific shapes shown in FIGS. 2 and 4 are merely two of the several configurations contemplated. The scope of the present invention is to be limited only by the extent of the following claims:

What is claimed is:

1. In a stuiferbox crimping apparatus for crimping a continuous tow of material comprising a stufferbox chamber for producing a crimp in said tow and having an inlet and an outlet for conducting the tow therethrough, a pair of parallel, rotatable yarn-gripping rollers located adjacent said inlet for feeding tow thereto, the improvement which consists of means associated with said rollers for producing an initial crimp in said tow transverse to the crimp produced in said stufferbox chamber.

2. The apparatus as defined in claim 1 in which said means is an irregular peripheral surface on each of the rollers.

3. The apparatus as defined in claim 2 in which one roller surface is concave and the other convex.

4. The apparatus as defined in claim 2 in which the surface of each roller consists of a plurality of ridges and grooves, the ridges of one roller surface opposing the grooves of the other.

5. In a stuiferbox crimping apparatus for crimping a yarn tow comprising a stufferbox chamber having an inlet and outlet for passage of yarn therethrough and a pair of rotatable feed rollers having substantially parallel opposed yarn-gripping surfaces on the circumference thereof for introducing yarn into the inlet of said stutter- -box, the improvement comprising at least one ridge on one of said feed rollers and at least one cooperating groove on the other of said feed rollers, with said ridge and groove extending circumferentially around respective feed rollers, the ridges of each surface intermeshing with the grooves of the opposing surface, and wherein the space between feed rollers is greater in the center of said yarn-gripping surfaces than at the edges thereof.

6. Apparatus as defined in claim 5 in which the surface of one roller is concave and the surface of the other roller is convex.

7. A method of simultaneously producing a complex multidirectional crimp to a filamentary tow for purposes of improving the bulk and web forming characteristics thereof, comprising:

(a) continuously feeding tow completely free of any crimp to a plural cooperating feeding roller means wherein a crimp is imparted to said tow in a direction perpendicular to a crimp subsequently produced in a stutfer box;

(b) maintaining the thus crimped tow in said stutfer box for a time sufficient to set the crimp imparted thereby; and

(c) removing the multidirectionally crimped tow from said stutter box.

References Cited UNITED STATES PATENTS 2,090,669 8/ 1937 Dreyfus et al. 28-72 2,575,781 11/1951 Barsch 28--72 2,547,285 8/1953 Pfau 28-72 3,234,626 2/ 1966 Paris 281 3,259,953 7/1966 Boer 28-1 MERVIN STEIN, Primary Examiner.

L. K. RIMRODT, Assistant Examiner. 

1. IN A STUFFERBOX CRIMPING APPARATUS FOR CRIMPING A CONTINUOUS TOW OF MATERIAL COMPRISING A STUFFERBOX CHAMBER FOR PRODUCING A CRIMP IN SAID TOW AND HAVING AN INLET AND AN OUTLET FOR CONDUCTING THE TOW THERETHROUGH, A PAIR OF PARALLEL, ROTATABLE YARN-GRIPPING ROLLERS LOCATED ADJACENT SAID INLET FOR FEEDING TOW THERETO, THE IMPROVEMENT WHICH CONSISTS OF MEANS ASSOCIATED WITH SAID ROLLES FOR PRODUCING AN INITIAL CRIMP IN SAID TOW TRANSVERSE TO THE CRIMP PRODUCED IN SAID STUFFERBOX CHAMBER. 